1. Field of the Invention
This invention relates to a vessel which normally contains a structural assembly under pressure higher than ambient, and has structure to allow the higher pressure to be vented to the atmosphere. More particularly, it is concerned with venting the pressure very quickly by allowing a component of the vessel to be moved away from the remaining portion of the vessel while limiting the distance the component will move.
2. Description of the Prior Art
A pressure vessel which normally maintains a low pressure (less than 20 p.s.i.) under extreme conditions may be subjected to a rapid and large increase in pressure. For example, an electrical recloser which is contained in a pressure vessel may have uncontrolled electrical arcing which in turn causes a pressure increase of up to 1000 p.s.i./sec.
It is desirable to vent this pressure while also retaining all the vessel parts. The rapid increase of pressure precludes the use of devices such as "pop-off" valves because such valves cannot vent a sufficient amount of gas quickly enough to prevent a catastrophic explosion.
A number of pressure relief devices have been proposed in the past for a variety of uses. In general, these units have been designed to relieve a relatively slow pressure build up and also maintain a sealed vessel after the excess pressure has been vented. However, these units have not met the needs for relieving a very large and fast build up of pressure.
One approach which has been proposed is connecting the component to the vessel using a nut and bolt with a sleeve placed between the nut and the vessel. The sleeve, which surrounds the stud bolt, will collapse and allow the component to separate and vent the pressure. A problem experienced with this approach is that the sleeve does not allow precise changes to be made in the pressure level to be vented and is expensive to install.